Signaling system.



R. M. HOPKINS. SIGNALING SYSTEM.-

APPLICATION FILED JUNE 28| I9l6.

1,21 5,658. Patented Feb. 13, 19 17.

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UNITED STATES PATENT OFFIQE,

RICHARD M. HOPKINS, OF NEW YORK, N..Y., ASSIGNOR TO AMERICAN DISTRICT TELE- GRAPH COMPANY, OF JERSEY CITY,,NEW. JERSEY, A. CORPORATION OF NEW JERSEY.

SIGNALING SYSTEM.

Specification of Letters Patent. 7

Patented Feb. 13, 1917.

Application filed June 28, 1916. Serial No. 106,333.

To all whom it may concern:

Be it known that I, RICHARD M. Horxms, a citizen of the United States of America, and a resident of New York, county of New York, and State of New York, have invented certain new and useful Improvements in Signaling Systems, of which the following is a specification. Y

My invention relates to signaling systems,

particularly those of the call box type, and

is applicable particularly to messenger call systems, burglar alarm systems, fire alarm systems, sprinkler supervisory systems, and other systems comprising transmitters, either automatically operated or hand operated, which are so constructed as not to require operation by a telegraph operator and of which a plurality are commonly placed in a single circuit, and are each arranged to transmit a characteristic signal to the central station. Inthe following description I will term these transmitters call boxes,,butit will be understood that in so doing I do not limit myself to any particular type of transmitter;th e particular construction of the transmitter itself forming no portion of the present invention.

My invention comprises improved means whereby a plurality of call box circuits, each containing, if desired, a plurality of callboxes, may transmit their signals to central station apparatus over-a single main circuit common to thesaid call box circuit.

The object of my invention is to simplify call box circuits and apparatus; to permit a single main circuit to transmit to a central station the signals of the call boxes or trans mitters of a plurality of call box circuits; and to provide a simple circuit arrangement for accomplishing this last mentioned ob 'ect. J I will now proceed to describe my invention with reference to the accompanying drawing showin diagrammatically a call box system embodying my invention.

In'the accompanying drawing, A and B designate the outgoing-and return lines of the main circuit; and either of these conductors may be considered the outgoing conductor and the other the return conductor. C and D designate branch circuits from the main circuit AB, each of these branch circuits containing call boxes, those in branch circuit C designated by numeral E, those in branch circuit D designated by numerals E.

I have not thought it necessary to illustrate the construction of these call boxes, since they may be of the usual type of box intended for so-called McCulloh service, 2'. 6., each box will have a double break wheel, one of which wheels is adapted to break and close the metallic circuit, the other to close and break the ground connection of the box. Such McCulloh service boxes are well known, tllie McCulloh system in itself being very o c.

Branch circuit C is connected to conductor A through a very high resistance 1, for ex: ample 5000 ohms, and said conductor 0 is connected to conductor B through a relatively low resistance 2, say for example, 500 ohms. Branch circuit D is connected to conductor A through a relatively low resistance 3, for example,- 500 ohms, and is connected to conductor B through a very high resistance 4, for example 5000 ohms. It makes no difference to which of the main conductors A and B either branch circuit C or D is connectechexcept that one branch circuit being connected to one of the main conductors A or B through a high resistance, the other branch circuit should be connected to that same main conductor through a low resistance. Each main circuit'conductor A or is provided with register-operating relays, those relays of conductor A being designated by numerals]? and G and those relays of conductor B being designated by numerals F and G. A generator I-I, indicated in this instance as a battery grounded at the middle, (though means for employing dynamo generators in place of the battery will readily occur to those skilled in the art) supplies current to conductors l A and B. Relays F and F have back dead C to be operated, the alternate making and breaking of the ground connection by the break wheel of that box through the 500 ohm resistance 2 will cause the operation of relay F; relay F not being operated be cause the current through the full circuit B, C, A, and battery H, is too feeble, owing to the resistance in that circuit, which includes the 5000 ohm resistance 1. It does not matter whether relays G and G operate or not, because under normal conditions signals of those relays are neglected.

Similarly (and this may occur simultaneously with the operation of a box in branch C) if one of the boxes E in branch I) be operat-ed, relay F will be operated through alternate closing and breaking of the ground connection during the sending of the signal by that box E.

Abnormal circuit operation.

Suppose branch C to be grounded at X. In that event, a box E to the right of the ground, it operated, will cause the operation of relay G through the alternate breaking and closing of the circuit from battery H to that ground X; relay F probably not operating under such condition, because not sufficiently sensitive. Boxes inbranch C to the left of the groiuid will operate relay G in similar manner, but will not operate relay F, that relay being too insensitive. While the ground exists in C, if one of the boxes in branch D be operated, relay F will respond as before, also, presumably, relay Gr; and distinction is made under such conditions, between operation of a box in grounded branch 0 and the operation of a box in ungrounded branch D, by observing whether relay G alone operates, or whether both relays F and G operate.

What I claim is 1. A signaling system such as described, comprising outgoing and return main circuit conductors with receiving means connected thereto, and a plurality of branch conductors connecting said main circuit conductors and each provided with a transmitter or transmitters, each such branch circuit conductor connected to one main circuit conductor through a relatively low resistance, and connected to the other main circuit conductor through a relatively high resistance, the low resistance of each such branch circuit conductor connected to that main circuit conductor to which the high resistance of the other branch conductor is connected.

2. A signaling system such as described, comprising outgoing and return main circuit conductors with a plurality of circuit receiving means connected to each, one such signal receiving means of each conductor arranged to operate upon an increase of current strength and the other to operate upon a decrease of current strength, and a plu-,

ral'ity of branch conductors connecting said mam circuit conductors and each provided with a transmltter or transmitters of the type which, when operated, both interrupt the main circuit through them and close a ground circuit connection, each such branch circuit conductor connected to one main circuit conductor through a relatively low resistance and connected to the other main circuit conductor through a relatively high resistance, the low resistance of each such branch circuit conductor connected to that main circuit conductor to which the high resistance of the other branch conductor is connected, and grounded current supply means for said main circuit conductors. In testimony whereof I have signed this specification in the presence of two subscribing Witnesses.

RICHARD M. HOPKINS. Witnesses:

WILLIAM J. STEWART, HARVEY R. EHRHART.

Copies 0! this patent may be obtained for five cents each, by addressing the Commissioner o! Patents Washington, D. 0." 

